74 Mr. Hatchett’s Experiments on the various Alloys, 
It is therefore certain, that tin, in small quantities, or even 
in the proportion of eight grains in the ounce Troy, is not by 
any means so injurious to the ductility of gold as was generally 
believed, previous to the publication of Mr. Alchorne’s Paper, 
in the Philosophical Transactions for the year 1784.* 
Some time after the experiments lately described were made, 
Robert Bingley, Esq. his Majesty’s Assay Master at the Mint, 
communicated to me the following experiments, made by him, 
in consequence of a paper published in the Memoirs of the 
Academy of Sciences at Paris for the year 1790, and in 
Nicholson’s Philosophical Journal, Vol. II. p. 140 and 179. 
The author of this paper, Mr. Tillet, a gentleman of much 
eminence in science, after having related some experiments 
which he purposely made upon mixtures of gold and tin, states 
it as his opinion, that tin, in small quantities, is really injurious 
to the ductility of gold, especially when gold thus alloyed is 
subjected to what he terms a cherry-red annealing heat ; and 
this circumstance, he conceives to have been overlooked by Mr. 
Alchorne. 
Mr. Bingley, whose professional accuracy is sufficiently 
* Gellert asserts, that even the fumes of tin destroy the ductility of gold. 
Metallurgic Chemistry, p. 368. The same opinion may also be found in the following 
works. 
Docimasie de Schlutter, traduit par Hellot, p. 284. E'lemens de Docimas- 
tique par Cramer. Tome I. p. 142. Neumann’s Chemistiy, Vol. I. p. 49 ; and, 
in page 125 of the same volume, he says, “ the minutest portion, even the vapour of 
“ tin, renders many ounces, and even pounds, of gold and silver, so brittle as to fall in 
“ pieces under the hammer The least particle of tin falling on the stones or luting 
“ of a furnace, will make all the gold and silver melted in it hard and brittle. From 
“ such an accident, the gold and silversmiths are obliged to pull down the whole 
“ furnace, and build a new one with fresh materials.” 
